This invention relates to a warning system for a camera having an electronic shutter which electrically controls the exposure and an automatic focusing device which electrically controls the focus of the photographing lense.
In cameras provided with an electronic shutter, a variety of methods which detect the brightness of the object to be photographed before the shutter release operation and actuate the warning device when the brightness is lower than a preselected level have been introduced. In automatic focusing systems, for instance, an automatic focusing system which controls the in-focus position by detecting the focus by means of photoelectric elements, it is necessary to give a warning as in the electronic shutter when automatic focusing is impracticable due to insufficient contrast between the brightness of the object and that of the background or because of insufficient brightness of the object itself.
A means to give the warning may be readily contrived by connecting warning means, such as lamps, to the luminance detecting unit and the in-focus detecting unit, respectively, so as to illuminate the lamps by the photographing impracticability signal given by those detecting units, however, this means has the disadvantages that the device is expensive and that the warning is liable to be missed to because the warning is given rather negatively; there is no positive warning to the camera user.